Merge pull request open-source-parsers#736 from maxim-ky/master

Move the existing value to "removed" argument; removed is optional (could be nullptr)

Author: cdunn2001

src/lib_json/json_value.cpp

@@ -1186,7 +1186,12 @@ bool Value::removeMember(const char* key, const char* cend, Value* removed)
   ObjectValues::iterator it = value_.map_->find(actualKey);
   if (it == value_.map_->end())
     return false;
-  *removed = it->second;
+  if (removed)
+#if JSON_HAS_RVALUE_REFERENCES
+    *removed = std::move(it->second);
+#else
+    *removed = it->second;
+#endif
   value_.map_->erase(it);
   return true;
 }